During Monson’s nearly 10-year presidential tenure, which ended with his death Tuesday night at age 90 of causes incident to age, Mormonism faced some of the most intense public scrutiny in its history — from a divisive vote over gay marriage to high-profile Mormon candidacies for president and a hotly debated policy for same-sex couples and their children. Still, the private prophet stayed largely behind the scenes, showing up unexpectedly at funerals, comforting the bereaved, visiting the sick and, before her death, caring for his wife, Frances....